Tools of the above generally mentioned kind are usually used for the machining of workpieces of metal, such as steel, aluminum, titanium, etc. The tools may either be fixedly mounted, e.g., for turning purposes, or be rotatable, e.g., for milling or drilling purposes. The parts included in the tools, which are interconnected via the serration connecting surfaces, usually consist of a basic body (at times a shim plate) and one or more cutting inserts. The cutting insert constitutes an article of consumption having a considerably shorter service life than the basic body serving as holder, and is, therefore, releasably connected to the basic body in order to enable exchange. Depending on the field of application, the cutting insert may have a most varying shape. Usually occurring embodiments consist of flat, polygonal or round cutting inserts of the type that has a top side, a bottom side and at least one side or circumferential surface extending between the same, which serves as a clearance surface, one or more cutting edges being formed in the transition between the top side and the clearance surface. Other cutting bodies may consist of rotatable so-called loose tops or cutting heads of the type that has a rotationally symmetrical envelope surface on which cutting edges are formed. Such cutting bodies are found, for instance, in drills, end milling cutters and the like.
It has always been an aim to connect the cutting insert or the cutting body to the basic body in an as rigidly and reliably way as possible. Previously, the conventional, flat cutting inserts were without exception formed with a smooth bottom side, the cutting inserts being mounted in seatings or so-called insert seats having a planar bottom against which the bottom side of the cutting insert was pressed, as well as one or more side support surfaces, against which the side surfaces of the cutting inserts were pressed. However, recently the use of co-operating serration connecting surfaces of the type initially mentioned has begun to be adopted in the tool industry.